Abstract
Aerosol particles are one of the major pollutants in outdoor and indoor air. They may negatively influence health, but also have negative effects on ecosystems and cultural heritage.
Particulate matter (PM) can be harmful for works of art by causing soiling and chemical damage, depending on particle size and chemical composition (Hatchfield, 2005). The aim of this study was to investigate concentrations and sources of airborne PM in two types of indoor environment of the National Museum (NM): a) in an exhibition hall in the centre of Prague and b) in a depository in a small town Terezin.
The measurements have been done during two intensive campaigns and included particle number concentrations and size distributions determined by a Scanning Mobility Particle Sizer (SMPS 3936, TSI, USA) and an Aerodynamic Particle Sizer (APS 3321, TSI, USA). Both instruments sampled alternately from indoor and outdoor, covering the size range 14 - 20,000 nm.
In NM Prague visiting hours took place every day from 10 am to 6 pm and the depository in NM Terezin is closed for public. In the NM Prague the results showed visitors as a source of coarse particles and traffic in the outdoor environment as the most probable source of fine particles.
In the NM Terezin the results indicated smoking in an adjacent office as an important source of fine particles. Average value for the indoor/outdoor ratio of the submicron particle number concentration had a maximum between particle diameters of 0.1 - 1 μm for both museums, which indicates a maximum penetration factor and low indoor deposition velocity of these particles.
During a day windows in Prague were mostly opened which resulted in a higher penetration than in Terezin. During the visiting hours in Prague the average indoor concentration of coarse particles was even higher than outdoors, which confirmed visitors as a source of these particles.